Bake a very simple library into the firmware.

modules/default.txt

@@ -1 +1 @@
-example.py
+multi-sensor-breakout/*.py

modules/py_frozen/boot.py

@@ -1,3 +1,9 @@
+import builtins
 import cppmem
+import explorer
+
+for k, v in explorer._exports.items():
+    setattr(builtins, k, v)
+
 # Switch C++ memory allocations to use MicroPython's heap
 cppmem.set_mode(cppmem.MICROPYTHON)

modules/py_frozen/explorer.py

@@ -0,0 +1,42 @@
+from picographics import PicoGraphics, DISPLAY_EXPLORER, PEN_RGB565
+from machine import Pin
+from micropython import const
+
+# We're only using a few colours so we can use a 4 bit/16 colour palette and save RAM!
+display = PicoGraphics(display=DISPLAY_EXPLORER, pen_type=PEN_RGB565)
+
+BUTTON_A_PIN = const(16)
+BUTTON_B_PIN = const(15)
+BUTTON_C_PIN = const(14)
+BUTTON_X_PIN = const(17)
+BUTTON_Y_PIN = const(18)
+BUTTON_Z_PIN = const(19)
+
+BLACK = display.create_pen(0, 0, 0)
+WHITE = display.create_pen(255, 255, 255)
+CYAN = display.create_pen(0, 255, 255)
+MAGENTA = display.create_pen(255, 0, 255)
+YELLOW = display.create_pen(255, 255, 0)
+RED = display.create_pen(255, 0, 0)
+GREEN = display.create_pen(0, 255, 0)
+BLUE = display.create_pen(0, 0, 255)
+
+_button_a = Pin(BUTTON_A_PIN, Pin.IN, Pin.PULL_UP)
+_button_b = Pin(BUTTON_B_PIN, Pin.IN, Pin.PULL_UP)
+_button_c = Pin(BUTTON_C_PIN, Pin.IN, Pin.PULL_UP)
+_button_x = Pin(BUTTON_X_PIN, Pin.IN, Pin.PULL_UP)
+_button_y = Pin(BUTTON_Y_PIN, Pin.IN, Pin.PULL_UP)
+_button_z = Pin(BUTTON_Z_PIN, Pin.IN, Pin.PULL_UP)
+
+_exports = {
+    "BLACK": BLACK,
+    "WHITE": WHITE,
+    "CYAN": CYAN,
+    "MAGENTA": MAGENTA,
+    "YELLOW": YELLOW,
+    "RED": RED,
+    "GREEN": GREEN,
+    "BLUE": BLUE,
+    "text": display.text,
+    "pen": display.set_pen
+}